The present invention relates to a device arranged for spraying or dispersing a fluid (e.g., a stain or dye). In particular, this invention relates to a delivery device arranged for spraying or dispensing the fluid to an intra-ocular surface in the anterior chamber of a human eye or another mammalian eye as part of a diagnostic or therapeutic endeavor (e.g., cataract surgery).
During intra-ocular surgery it is often desirable to distinguish between different intra-ocular structures. One means of accomplishing this desired effect is to use an adjuvant dye or stain to differentiate between different structures. There are several different types of dyes used to stain intra-ocular structure, including but not limited to fluorescein, indocyanine green, methylene blue, and trypan blue. A list of some other possible dyes includes indigotindisulfonate, rose bengal, patent blue V, sulphan blue, tolonium chloride, lissamine green, brilliant blue, carbanthrene blue, erythrosine, and alphazurine.
One type of such an intra-ocular surgery is cataract surgery. In modern cataract surgery, it is desirable to easily distinguish the anterior lens capsule from surrounding structures and perform a continuous curvilinear capsulorrhexis so that the natural lens can be removed by phacoemulsification or other methods and replaced with an artificial lens.
A method of cataract surgery is as follows. A small paracentesis incision is made peripherally into the clear cornea. The aqueous humor of the anterior chamber is subsequently drained and replaced with air. A dye is then applied to the anterior lens surface (e.g., anterior lens capsule) using a delivery device (e.g., a syringe). The dye is allowed to contact the lens surface for an amount of time sufficient to stain that surface. Optionally, the dye solution is drained or irrigated (using balanced salt solution) from the anterior chamber. Next, the anterior chamber is filled with an optically clear viscoelastic polymer (e.g., hyaluronate, chondroitin sulfate). A rent is made in the anterior lens capsule using a cystotome and a continuous curvilinear capsulorrhexis is the made under direct visualization of the stained anterior lens capsule. Removal of the natural lens material may be accomplished by a variety of methods including phacoemulsification.
In the above-outlined step of removing the aqueous humor from the anterior chamber and replacing it with air, the lens assumes a convex configuration. This occurs because the fluid from the anterior chamber is replaced with air and the pressure in this compartment of the eye is lower than the pressure in the vitreous compartment of the eye and the lens is pushed forward. This physical phenomenon of the lens assuming a convex configuration can cause difficulty with the application of a dye or stain to the anterior lens capsule surface.
When the fluid dye or stain is applied to the anterior lens surface of an air-filled anterior chamber, it tends to roll off to one side and collect in the gutter space created by the iris lens interface and the angle of the anterior chamber. Because of this, the dye or stain must be massaged into the capsule to achieve adequate staining. This maneuver of massaging the dye into the lens capsule causes the risk of inadvertently tearing the capsule and thereby complicating the remainder of the surgical procedure. Also, a larger volume than is necessary to adequately stain the lens capsule must be utilized.
Furthermore, the current method of delivering a fluid dye or stain to the anterior chamber to stain the anterior lens capsule is accomplished in an uncontrolled fashion. The dye or stain is applied to the surface of the anterior lens capsule for an amount of time sufficient to stain that surface. Because of the current design of the tip of the cannula, the dye or stain encounters intra-ocular structures that are not intended and may have a deleterious effect, including a toxic effect as well as diminishing the effect of selective staining.
The preferred delivery devices are arranged to dispense a dye or stain in a controlled fashion to a target tissue or structure (e.g., anterior lens capsule) located in the anterior chamber of an eye for differentiating the target tissue or structure during a surgical procedure or any diagnostic or therapeutic endeavor. The device is designed to control the area to which the dye or stain can be delivered, thereby eliminating detrimental effects resulting from dispensing the dye or stain in an undesired area. The delivery device is constructed to have the dye or stain exit from an orifice located on an inferior surface of the cannula as opposed to a currently used dispensing orifice located at the distal tip of the cannula. This new location allows an operating surgeon to more precisely control the area to which the dye or stain is applied, thereby sparing the neighboring intra-ocular structures from unwanted staining. A preferred dye for staining the target tissue or structure is indigo carmine, as discovered by the inventor of the present invention.
In an exemplary embodiment, a dispensing device arranged to deliver a fluid into an eye includes a reservoir, a cannula and a pressurizer. The reservoir is arranged to house the fluid to be delivered. The a cannula has a distal tip for insertion into the eye, is in fluid communication with the reservoir and includes an orifice located inward of the cannula""s distal tip. The pressurizer (e.g., plunger or mechanism that applies pressure into the reservoir) is arranged to move the fluid from the reservoir through the orifice to an intra-ocular structure within the eye.
The cannula has a distal portion extending from a location inward of the orifice to the distal tip. As such, the device may also include a fin extending longitudinally around the distal portion. Further, the orifice may include a sleeve surrounding and extending from the orifice in a direction desired for the fluid delivery. Preferably, this sleeve is flared outward from the orifice.
Moreover, the orifice of the invention is preferably designed to disperse the dye or stain in a spray form rather than stream form, so as to allow the dye or stain to better adhere to the tissue or structure. In other words, the orifice is preferably arranged with an opening having a size and shape sufficient to discharge liquid in spray form. This feature obviates the need to massage the dye into the lens capsule and prevents the possibility of the complication of inadvertently tearing the lens capsule. Also, this spray feature further prevents the dye or stain from leaking onto adjacent tissue; thereby staining tissue or structures not intended to be stained. This spray feature also allows for delivery of a smaller amount of the dye or stain to the intra-ocular compartment, thereby reducing any potential toxic effect of the dye or stain.
In another exemplary embodiment, a method for delivering a fluid to an intra-ocular structure is disclosed. The method uses a spray device having the fluid in a reservoir, a cannula in fluid communication with the reservoir and having a distal tip and an orifice located inward of the distal tip, and a pressurizer arranged to move the fluid from the reservoir through the orifice. The method includes inserting the cannula through an opening of an eye, aligning the orifice over the intra-ocular structure, and spraying the intra-ocular structure with the fluid by moving the fluid from the reservoir through the orifice.
In yet another exemplary embodiment, a spray device arranged to deliver a fluid into a cavity includes a reservoir, a cannula and a pressurizer. The reservoir is arranged to house the fluid to be delivered. The cannula has a distal tip for access into the cavity, is in fluid communication with the reservoir, and includes an orifice located inward of the distal tip. The pressurizer is arranged to move the fluid from the reservoir through the orifice to a tissue within the cavity.
The described characteristics of the invention are easily discernable from the drawings. Moreover, further scope of applicability of the present invention will become apparent in the description given hereafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since the invention will become apparent to those skilled in the art from this detailed description.